i [3]i [4] in middle.

Meaning of the parameters is as follows:

• prefix - string (usually at least header field name). Xl_lib formatting supported.

• suffix - string (usually at least line terminator). Xl_lib formatting supported.

i [5].

Example 11. is_present_hf usage

...
if (method == "REGISTER" ) {
    # Many user agents can use the Date header field
    # in 200 OK replies to REGISTER to synchronize
    # internal clock
    append_time();
};
...

1.2.12. append_hf_value(hf, xl_value)

Append new header value after an existing header, if no index acquired append at the end of list. Note that a header may consist of comma delimited list of values.

Meaning of the parameters is as follows:

• hf - Header field to be appended. Format: HFNAME [ [IDX] ]. If index is not specified new header is inserted at the end of message.

• xl_value - Value to be added, xl_lib formatting supported.

Example 12. append_hf_value usage

...
append_hf_value("foo", "gogo;stamp=%Ts")   # add new header
append_hf_value("foo[1]", "gogo")  # add new value behind first value
append_hf_value("foo[-1]", "%@Bar") # try add value to the last header, if not exists add new header
...

1.2.13. insert_hf_value(hf, xl_value)

Insert new header value before an existing header, if no index acquired insert before first hf header. Note that a header may consist of comma delimited list of values. To insert value behing last value use appenf_hf_value.

Meaning of the parameters is as follows:

• hf - Header field to be appended. Format: HFNAME [ [IDX] ]. If index is not specified new header is inserted at the top of message.

• xl_value - Value to be added, xl_lib formatting supported.

Example 13. insert_hf_value usage

...
insert_hf_value("foo[2]", "gogo")
insert_hf_value("foo", "%$an_avp")   # add new header at the top of list
insert_hf_value("foo[1]", "gogo") # try add to the first header
...

1.2.14. remove_hf_value(hf_par)

Remove the header value from existing header, Note that a header may consist of comma delimited list of values.

Meaning of the parameters is as follows:

• hf_par - Header field/param to be removed. Format: HFNAME [ [IDX] ] [. PARAM ] If asterisk is specified as index then all values are affected.

Example 14. remove_hf_value usage

...
remove_hf_value("foo")  # remove foo[1]
remove_hf_value("foo[*]")  # remove all foo's headers
remove_hf_value("foo[-1]") # last foo
remove_hf_value("foo.bar")  # delete parameter
remove_hf_value("foo[*].bar") # for each foo delete bar parameters
...

1.2.15. remove_hf_value2(hf_par)

Remove specified header or parameter. It is expected header in Authorization format (comma delimiters are not treated as multi-value delimiters).

Meaning of the parameters is as follows:

• hf_par - Header/param to be removed. Format: HFNAME [ [IDX] ] [. PARAM ] If asterisk is specified as index then all values are affected.

Example 15. remove_hf_value2 usage

...
remove_hf_value2("foo")  # remove foo[1]
remove_hf_value2("foo[*]")  # remove all foo's headers, the same as remove_hf_header("foo[*]");
remove_hf_value2("foo[-1]") # last foo
remove_hf_value2("foo.bar")  # delete parameter
remove_hf_value2("foo[*].bar") # for each foo delete bar parameters
...

1.2.16. assign_hf_value(hf, xl_value)

Assign value to specified header value / param.

Meaning of the parameters is as follows:

• hf_para - Header field value / param to be appended. Format: HFNAME [ [IDX] ] [. PARAM] If asterisk is specified as index then all values are affected.

• xl_value - Value to be assigned, xl_lib formatting supported. If value is empty then no equal sign apears in param.

Example 16. assign_hf_value usage

...
assign_hf_value("foo", "gogo")  # foo[1]
assign_hf_value("foo[-1]", "gogo")  # foo[last_foo]

assign_hf_value("foo.bar", "")
assign_hf_value("foo[3].bar", "")
assign_hf_value("foo[*]", "")  # remove all foo's, empty value remains
assign_hf_value("foo[*].bar", "")  # set empty value (ex. lr)
...

1.2.17. assign_hf_value2(hf, xl_value)

Assign value to specified header. It is expected header in Authorization format (comma delimiters are not treated as multi-value delimiters).

Meaning of the parameters is as follows:

• hf_para - Header field value / param to be appended. Format: HFNAME [ [IDX] ] [. PARAM] If asterisk is specified as index then all values are affected.

• xl_value - Value to be assigned, xl_lib formatting supported. If value is empty then no equal sign apears in param.

Example 17. assign_hf_value2 usage

...
assign_hf_value2("Authorization.integrity-protected", "\"yes\"")
assign_hf_value2("foo[-1]", "gogo")  # foo[last_foo]
assign_hf_value2("foo[*].bar", "")  # set empty value (ex. lr)
...

1.2.18. include_hf_value(hf, xl_value)

Add value in set if not exists, eg. "Supported: path,100rel".

Meaning of the parameters is as follows:

• hf - Header field name to be affected.

• value - xl_lib formatting supported.

Example 18. include_hf_value usage

...
include_hf_value("Supported", "path");
...

1.2.19. exclude_hf_value(hf, xl_value)

Remove value from set if exists, eg. "Supported: path,100rel".

Meaning of the parameters is as follows:

• hf - Header field name to be affected.

• value - xl_lib formatting supported.

Example 19. exclude_hf_value usage

...
exclude_hf_value("Supported", "100rel");
...

1.2.20. hf_value_exists(hf, xl_value)

Check if value exists in set. Alternate select @hf_value_exists.HF.VALUE may be used. It returns one or zero.

Meaning of the parameters is as follows:

• hf - Header field name to be affected. Underscores are treated as dashes.

• value - xl_lib formatting supported.

Example 20. hf_value_exists usage

...
if (hf_value_exists("Supported", "100rel")) {

}

if (@hf_value_exists.supported.path == "1") {

}
...

1.2.21. @hf_value selects

Get value of required header-value or param. Note that functions called 'value2' works with Authorization-like headers where comma is not treated as value delimiter. Formats: @hf_value.HFNAME[IDX] # idx value, negative value counts from bottom @hf_value.HFNAME.PARAM_NAME @hf_value.HFNAME[IDX].PARAM_NAME @hf_value.HFNAME.p.PARAM_NAME # or .param., useful if requred called "uri", "p", "param" @hf_value.HFNAME[IDX].p.PARAM_NAME # dtto @hf_value.HFNAME[IDX].uri # (< & > excluded) @hf_value.HFNAME[*] # return comma delimited list of all values (combines headers) @hf_value.HFNAME # the same as above [*] but may be parsed by cfg.y @hf_value.HFNAME[*].uri # return comma delimited list of uris (< & > excluded) @hf_value.HFNAME.uri # the same as above [*] but may be parsed by cfg.y @hf_value.HFNAME[IDX].name # returns name part, quotes excluded @hf_value.HFNAME.name # returns name part of the first value @hf_value2.HFNAME # returns value of first header @hf_value2.HFNAME[IDX] # returns value of idx's header @hf_value2.HFNAME.PARAM_NAME @hf_value2.HFNAME[IDX].PARAM_NAME @hf_value.HFNAME[IDX].uri # return URI, quotes excluded @hf_value.HFNAME.p.uri # returns param named uri, not URI itself @hf_value.HFNAME.p.name # returns param named name, not name itself @hf_value.HFNAME[IDX].uri.name # any sel_any_uri nested features may be used @hf_value.HFNAME[IDX].nameaddr.name # select_any_nameaddr

Meaning of the parameters is as follows:

• HFNAME - Header field name. Underscores are treated as dashes.

• IDX - Value index, negative value counts from bottom

• PARAM_NAME - name of parameter

Example 21. @hf_value select usage

...
$a = @hf_value.my_header[1].my_param;
xlog("L_ERR", "%@hf_value.via[-1], %@hf_value.from.tag\n");
$b = @hf_value.p_associated_uri;

xlog("L_ERR", "Route uris: '%@hf_value.route[*].uri'\n");
$rr = @hf_value.route.uri;

$prt = @hf_value2.authorization.integrity_protected;
...